Blown fuse signal



4, 1934- w. M. JAMES 1,970,007

BLOWN FUSE SIGNAL Filed Oct. 5, 1933 fly hisAZ rneys' Patented Aug. 14, 1934 PATENT OFFICE BLOWN FUSE SIGNAL William M. James, Excelsior, Minn.

Application Gctober 5, 1933, Serial No. 692,305

4 Claims.

My invention relates to signal devices for indicating the rupture of electrical fuses and particularly to visual signal devices for identifying exposed link type fuses which have blown.

5 It is the practice of many power companies to provide sectionalizing fuse cutouts in their low voltage overhead distribution lines between sections of the lines fed from different transformers in order that the various transformers may normally feed the load in parallel. and yet a section which becomes faulty may be automatically isolated from all other sections. Such sectionalizing fuses are of necessity located on the lines adjacent the tops of poles and hence a blown fuse may be detected by a man on the ground only with considerable difiiculty if at all. Since each section of the line is served by its own transformer, fuses blown by a temporary fault will not give evidence of their blowing by outage of service and may pass unnoticed for a considerable period of time. These fuses are usually of the exposed strip or link type.

It is an object of my invention to provide a simple, effective, rugged and inexpensive signal device for automatically giving evidence readily visible at a distance of the blowing of a strip or link type fuse.

Another object is to provide such a device which is released for signalling action by the blowing of the fuse, which remains in signalling position until reset and which cannot be reset unless the fuse is renewed.

Yet another object is to provide such a device wherein a brightly colored indicating target is normally retained in hidden position and is released to move into visible position when the device operates.

A further object is to provide such a device which may be readily attached to or detached from a fuse cutout without the use of tools.

A still further object is to provide such a device which will improve the current interrupting action of the fuse with which it is used.

These and other objects and advantages of the invention will be more fully set forth in the following description made in connection with the accompanying drawing, in which like reference characters refer to similar parts throughout the several views, and in which:-

Fig. l is a side view of one type of overhead line sectionalizing fuse cutout with an embodiment of my invention attached thereto and disposed in its normal or unoperated position;

Fig. 2 is a sectional view taken on the line 22 of Fig. l, as indicated by the arrows;

Fig. 3 is a front view of my device in operated position, and

Fig. 4 is a side view of my device in operated position.

Referring to the drawing and particularly to Fig. 1, two wires W, respectively connected with adjoining sections of an overhead electric power line are mechanically connected together but electrically insulated from each other by means of the strain insulator I. Adjacent each side of 6 the strain insulator I an elbow-shaped metal arm A carrying a wire gripping clamp C at its upper end is mechanically and electrically connected to a short bared portion of the wire by means of the clamp C. The lower ends of the respective arms A extend toward each other and are mechanically connected together but electrically insulated from each other by means of a flat rectangular bar or fuse base B formed of insulating material. The bar B is connected at each of its 7 5 ends to one of the arms A by means of a nutted bolt D which extends through suitable apertures the bar 13 and the arm A. A thumb-nut E is placed on the free end of each of the bolts D and the ends of a fusible element or fuse link L are clamped between the respective thumb-nuts E and the nuts on the bolt D. The above described fuse cutout is of well known standard construction.

My blown fuse indicator, shown independently of the fuse cutout in Figs. 3 and 4 and shown in operative relation with the fuse cutout in Figs.

1 and 2, includes two similar flat elements shown in the drawing as disks 5 and '6. The disks 5 and 6 will hereinafter be respectively referred to as 0 the inner disk and outer disk.

The outer disk 6 carries on its outer side an arcuate abutment member 60. either secured thereto or formed integrally therewith.

The disks5 and 6 and the abutment member 6a are formed of bakelite or of other electrically nonconductive material having heat resistant properties at least to a moderate degree and preferably of a weather resistant nature.

For the purpose of attachment to the base 13 of a fusecutout the inner disk 5 carries on its inner side an attachment clip 7 formed of a reversely bent strip of spring metal, one leg of which is secured to the disk 5 by suitable means and the other or free leg of which is adapted to engage the rear side of the base B of a fuse cutout, The end of the leg of the clip 7 which is secured to the disk 6 carries an inturned lip 7a situated substantially flush with the edge of the disk 6 and adapted to engage the upper edge of the base B of a fuse cutout.

The disks 5 and 6 are connected together by a spring member such as the helical spring 8 rigidly secured at its end portions to the edges of the respective disks, as by means of pegs 8a as shown in Fig. 3. The spring 8 is arranged to urge the disks 5 and 6 toward the relative positions shown in Figs. 3 and 4 and is under tension when the disks are swung to the relative positions shown in Figs. 1 and 2.

The relative positions of the disks 5 and 6 as shown in Fig. 2 are the positions in which the disks are normally disposed when the device is in operative relation with a fuse cutout. The sides of the respective disks which face each other when the disks are in this position are enameled or otherwise colored in bright hues which are best adapted for visibility from a relatively long distance. The coloring of one disk may be selected for good visibility in daylight and the coloring of the other disk may be selected for good visibility at night when illuminated by a beam of light from a flashlight or spotlight. A bulls-eye design such as indicated in Fig. 3 may be used. All parts of the device other than the one brightly colored face of each disk should be colored in a dull inconspicuous color.

In normal use my signal device is placed on a fuse cutout by swinging the disks 5 and 6 to the relative positions shown in Fig. 2 against the tension of the spring 8, spreading the spring clip '7 and then placing the device on the fuse cutout in the position shown in Figs. 1 and 2. The inturned car 7a of the spring clip 7 will engage the upper edge of the base B of the fuse cutout to prevent the device from slipping downwardly. The abutment member 6a carried by the outer disk 6 is urged by the spring to bear outwardly against the medial portion of fuse link L and the link L restrains the outer disk 6 from being moved by the spring 8 to the position shown in Figs. 3 and 4. With the disks in normal position the brightly colored faces thereof are concealed and only the dully colored portions of the device are exposed.

If the fuse blows the link L is ruptured and releases the device to assume the position shown in Figs. 3 and 4. In this position the brightly colored face of each disk is exposed and presents a visible indication that the fuse has blown.

In addition to the function of providing a visual blown fuse signal my device is capable of providing improved operation of the fuse. When the fuse link is heated by an overload current to a temperature at which it is soft andwould ordinarily sag, my device through the pressure with which the abutment element 6a bears against the fuse link forces rupture of the link. Also, the abutment element 6a and the disk 6, which are both formed of heat resistant insulating material, operate to rupture any are incidental to the blowing of the fuse and to force the remaining stubs of the blown fuse element apart to a considerable distance. The above described actions take place with great rapidity and consequently result in very rapid interruption of an excessive current.

It is obvious that my signal device is readily adaptable for use with any type of fuse cutout in which an exposed fuse link is used.

It is apparent that I have invented a novel, simple, rugged and inexpensive visual blown fuse signal device which may be easily attached to a fuse cutout without the use of tools which provides an indication which is readily visible at a considerable distance and which improves the operation of a fuse with which it is used.

It will, of course, be understood that various changes may be made in the form, details, proportions and arrangement of the parts, without departing from the scope of my invention, which generally stated, consists in a device capable of carrying out the objects above set forth and in the novel parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:-

1. A blown fuse indicator for a fuse cutout having a base and a fusible link supported adjacent said base comprising a target element normally abutting said link and retained thereby in a position between said fusible link and said base, the respective sides of said target element being contrastingly colored, one of said sides being normally exposed, and means urging said element away from said base whereby rupture of said fusible link will release said target element for movement away from said base to expose a different side of said target element to view than the side normally exposed when said link is intact.

2. In combination with a fuse cutout having a base and a fusible link supported adjacent said base, a blown fuse indicator comprising a pair of target elements adapted to be retained between said fusible link and said base, a spring clip secured to the one of said elements adjacent said base for attaching the same to said base, a lip on said clip for engaging the edge of said base to prevent accidental detachment of said clip from said base, and means urging said elements apart whereby rupture of said fusible link will release the outer one of said elements for out ward movement.

3. In combination with a fuse cutout having a base and a fusible link supported adjacent said base, a blown fuse indicator comprising a pair of target elements normally retained between said fuse link and said base in substantially parallel relation to each other and to said base, an abut ment member for engaging the medial portion of said link carried by and extending outwardly of the outer one of said elements, a spring clip secured to the inner one of said elements and gripping said base and a spring connecting aligned edge portions of the respective ones of said elements and normally under tension to urge if said elements to swing apart, the mutually facing sides of the respective ones of said elements being colored so as to be readily visible whereby rupture of said link will release said elements to be swung apart by said spring to expose the colored faces adapted to be normally disposed parallel to each other and to said base in the space between said link and said base, normally mutually facing faces of said targets being brightly colored, said target ltd elements normally cooperating to conceal the respective brightly colored faces of each other, means for attaching the one of said elements ad jacent said base to said base and means urging the other of said elements outwardly against said link whereby rupture of said link will release said last mentioned element for outward movement 

